As physiological factors where a person sees objects three-dimensionally, there are binocular parallax, accommodation, convergence, motion parallax, and the like. A factor which most influences three-dimensional appearance among physiological factors in stereoscopic vision is binocular parallax for which three-dimensional information is obtained from difference in images in the horizontal direction seen by the left and right eyes. Accordingly, methods in which binocular parallax is used are the most common as three-dimensional display methods.
In a three-dimensional display method in which binocular parallax is used, an image for the left eye and an image for the right eye are displayed on one screen, and the left eye and the right eye see the respective corresponding images so that a combined image is three-dimensional. Accordingly, it is necessary for a person who sees a screen to wear special glasses so that the left eye and the right eye see different images.
Further, a display device for three-dimensional images, for which a person does not need to wear glasses, has been known. In such a display device for three-dimensional images, an optical component such as a parallax barrier, a lenticular lens, a micro lens array, or a fly eye lens is used to control a traveling direction of light from a screen, whereby the left eye and the right eye see different images, and stereoscopic vision is obtained (see Patent Document 1: Japanese Published Patent Application No. H8-036145).